In this image a hand is held up to the forehead and, to the right, part of a foot can be seen. The groove between the nose and the upper lip is visible and the nose has the characteristic “button” shape. It looks cramped in there but there is still room to move.

Your baby is cushioned in a sac of amniotic fluid, which surrounds her until your waters break and you go into labour.

As your uterus has enlarged throughout your pregnancy, the amniotic sac has expanded to accommodate both your baby and the amniotic fluid. From now on, however, the sac will grow by simply stretching rather than forming new cells.

The amniotic sac is formed from two distinct layers or membranes, an inner “amnion” and outer “chorion”. The chorion originally had a blood supply of its own, but this has now been lost. The thinner amnion is able to slide over the chorion as your baby pushes against it. Neither layer contains nerve cells: this explains why it’s not painful when your membranes rupture or “waters break”.

Combined, the layers are only 0.5mm thick. Collagen fibres in each layer allow for a great deal of stretch – this is vital in these final months to avoid early rupture of the membranes. Indeed, the membranes may be so resistant to rupture that they don’t break until the final stages of your labour.

As well as holding in the amniotic fluid and providing a barrier to possible infection through the cervix, the membranes contain substances that form prostaglandins. Prostaglandins play an important part in the initiation of labour. This is one of the reasons why labour often starts when the membranes have ruptured.

The only reliable way to discover the sex of your baby is to have a diagnostic test, such as amniocentesis or chorionic villus sampling.

Even ultrasound can be wrong. And despite the common belief that the size and shape of your bump indicates the baby’s gender, these are in fact determined by your muscle tone, your baby’s position, and the amount of weight you’ve gained.

By now, it’s possible to see and feel your baby moving, often with kicks and punches. This may happen more often in the evenings, when your partner finally gets to sit down and relax. Watching your baby’s movements can be a great way to bond with her, and with your partner.

Your baby will respond to your voice, to music, and may even jump at unexpected noises; it’s impossible to say whether this is because these noises are enjoyed or because they’re irritating.

Your baby will also hiccup sometimes and you have a better chance of feeling her moving while she’s hiccuping than during any other form of movement. This is because hiccups occur over prolonged periods of time, while kicks and punches can be fairly random.

Your baby may have several episodes of hiccuping in a day, or only one or two – you will both be able to feel these as a series of light, rhythmic movements.